ATCvet code:
QP52AC13 –
Pharmacodynamics
Fenbendazole is an anthelmintic belonging to the benzimidazole-carbamate group. It acts by interfering with the energy metabolism of the nematode.
Fenbendazole inhibits the polymerisation of tubulin to microtubules. This interferes with essential structural and functional properties of the cells of helminths, such as formation of the cytoskeleton, formation of the mitotic spindle and the uptake and intracellular transport of nutrients and metabolic products. Fenbendazole has activity against Ascaridia galli (adult stage) and Heterakis gallinarum (L5 and adult stages) in chickens and against H. gallinarum (adult stage) in pheasants.
Pharmacokinetics
After oral administration fenbendazole is only partially absorbed. Following absorption, fenbendazole is rapidly metabolised in the liver mainly to its sulphoxide (oxfendazole) and further to its sulphone (oxfendazole sulphone). In chickens oxfendazole sulfone is the main component detected in plasma, accounting for about 3/4 of the total AUC (ie the sum of the AUC for fenbendazole, oxfendazole and oxfendazole sulphone). Fenbendazole and its metabolites are distributed throughout the body, reaching highest concentrations in the liver.
The elimination of fenbendazole and its metabolites occurs primarily via the faeces.